Overview
ISO 14577-5:2022 - "Metallic materials - Instrumented indentation test for hardness and materials parameters - Part 5: Linear elastic dynamic instrumented indentation testing (DIIT)" specifies a standardized method for measuring dynamic indentation hardness (Hd) and dynamic reduced modulus (Erd) using oscillatory (harmonic) excitation of the indenter. The method applies when an oscillatory force or displacement is imposed while the test load or displacement is held at a target value or during continuous loading. DIIT extends instrumented indentation testing (IIT) to extract elastic–plastic material parameters from the frequency response of the contact.
Key topics and technical requirements
- Scope and principle: Applies to materials showing elastic‑plastic behaviour where small harmonic oscillations are applied and the transfer function (force/displacement) is used to calculate dynamic contact stiffness (Sd), Hd and Erd.
- Dynamic model: Uses a single‑degree‑of‑freedom harmonic oscillator to model actuator + indenter dynamics; actuator parameters (support stiffness ks, damping D, oscillating mass m) must be known or estimated (Annex A).
- Testing machine capabilities:
- Must drive the actuator at prescribed frequency and amplitude and measure resulting dynamic displacement or force.
- Calibration required for dynamic force, dynamic displacement and frequency per ISO 14577-2.
- Compensation/validation of phase differences introduced by electronics (phase‑lock amplifier or equivalent) is mandatory.
- Interferometer or calibrated cantilever methods can be used for direct dynamic calibration.
- Data evaluation:
- Dynamic contact stiffness Sd is derived from measured transfer function; contact depth hdc is corrected (ε correction) and projected contact area A(h) is used to compute Hd and Erd.
- Oscillation amplitude must be smaller than elastic recovery to maintain contact.
- Uncertainty estimation and reporting requirements are covered (Annex B and clause 8).
- Test procedures: Stepwise loading, hold periods or constant strain‑rate loading can be combined with DIIT measurements (clause 7).
Applications and who uses it
- Materials characterization: Determining indentation hardness and indentation modulus for metallic and coated materials, particularly when elastic properties at small scales are critical.
- Research & development: R&D labs studying elasto‑plastic response, frequency‑dependent contact behavior or time‑dependent mechanical properties.
- Quality control and certification: Industrial testing labs, instrument manufacturers, and accreditation bodies implementing reproducible DIIT protocols.
- Micro/nano‑indentation testing: Instruments employing dynamic excitation for higher sensitivity in thin films, surface treatments and small volumes.
Keywords: ISO 14577-5:2022, dynamic instrumented indentation testing, DIIT, indentation hardness, indentation modulus, dynamic contact stiffness, instrumented indentation, testing machine calibration, materials characterization.
Related standards
- ISO 14577-1 - Test method (general IIT)
- ISO 14577-2 - Verification and calibration of testing machines (referenced for dynamic calibration)
- ISO 14577-3 - Calibration of reference blocks
- ISO 14577-4 - Test method for coatings
- ISO/IEC Guide 98-3 (GUM) - Uncertainty of measurement